X-ray apparatus



sept. 11, 1951 2,567,566

A. J. KIZAUR X-RAY APPARATUS Filed July l5, 1949 2 Sheets-Sheet 1 v W Y i Y Y A. J. KIZAUR X-RAY APPARATUS Sept. '11, 1951 2 Sheets-Sheet 2 Filed July l5, 1949 EIIIII. :IFI

Patented Sept. 11, .1951

UNITED STATES. PATENT ornce X-RAY APPARATUS Arthur J. Kizaunwauwatosa, Wis., assignorto General Electric Company, a corporation. of

New York Application July 15, 1949, Serial No. 104,903

6 Claims.

The. present. invention relates in general to.

'may be disposed, the frame and panel being preferably, thoughnotnecessarily, supported for tilting movement, sothat an objectthereon may be presented atwill either, horizontally or in tilted c positionA for examination.

X-'r'ay examination may be accomplished by means. ofa suitable X-ray source mounted in position above the panel to emit an X-ray beam downwardly through the panel and the obj ect disposed Ythereon for examination, to thereby photograph an X-ray picture of the object on X-ray sensitive material' supported beneath the panel.

Examination may also be accomplished'by means ofA afsuitable X-.ray source mounted in position beneath the panel and the object disposed thereon for examination, for X-ray. photography or fluoroscopy onsuitable X-rayv sensitive material disposed above the object being examined.

For examination convenience and flexibility, the structure is preferably arranged to allow for examination at will by either of the aforesaid methods, and to this end the structure may in- :cludesuitable X-raysource means disposable at will above or below the'panel or top of the table; or separateV X-rayV sources, one disposed above and the other below the'panel, may be provided. In order that examination may be accomplished inu any zone or area within theconfines of the table top, it is desirable that the X-ray source or sources be adjustable longitudinally as well as laterally` of the table top within the area thereof; it beingy likewise desirable to provide carriage means allowingfor the lateral and longitudinal adiustment of thesensitivematerial at all times in registration or fixed relation with respect to the .cooperating source., ofv X-rays.

Tofthis end. the structure may include carrying-f frame means,y preferably supported onthe .table frame and adjustable longitudinally with respect to thev table,Y top. The sensitive material and cooperating X-ray; source means may be supportedonsuchcarrying frame means or may be .separately supported.- Such carrying frame means (Cl. Z50- 58) may include separate carriage, one of which may be mounted on the table frame for movement longitudinally thereof beneath the tabletop panel, for the purpose of supporting X-ray sensitive material, as in a light-tightcassette, in position beneath the table top to cooperate with` an X-ray source disposed. above the table. Such a carriage may include a Bucky: type diaphragmin position to rectify X-rays prior to impingement thereof uponthe sensitive material disposed in the carriage beneath the diaphragm; and thek carriage may also contain diaphragm shifting;

and other electrically operated mechanism. Such carriage, for convenience, maybe referredtoas an under panel cassette carriage, andmay be mounted for movement. onsuitable rails on the table frame. It may be shifted andlocked. in adjusted position, and otherwise controlled by means of handles. extending outwardly of. `and beneath a side edge of. the table top panel, through a suitable. elongatedslot. or openingv between the edge ofitheV panel and its. underlying support frameL such. operating and control handles being thus conveniently located atapproximately table top height in position readily accessible to an operator of the apparatus standing beside the table structure. c A separate, longitudinallymovable frame structure may be provided for carrying sensitive material above the table top panel; f Such frame, for convenience, may be referred to as an over panel support structure, but it preferably also includes portions extendingl beneath the top panel for the mounting o1" an X-ray source beneath the panel in position registeringwith the sensitive material disposed above thepanel.

It will be apparent that, in order to avoid operational interference, the separate carriage structures should be movable from one end of thetable. structure to the other, independently the one with respect to the other; and it will be apparent, also,

that when one of the structures is in position for examination, the other should be in relatively olset position to avoid interference by oneLcar.- riage structure` with anexaminationbeing conducted by the other. Accordingly, when, for example, an examination is being conducted by. means of. the over panel support structure, the under panel cassette carriage should beoiset at either of the ends of the table structure, thereby allowing examination. withthe over panel *support structure to take place at thecentral por.- tions of the table, or at. the end thereof remote from the under panel cassette carriage,V and vice versa.

It will be noted that when the over panel support structure is in operation, an X-ray source will be activated in position beneath the panel to direct X-rays upwardly upon sensitive material mounted above the table. This sensitive material may be either a fluorescent screen upon which to visually observe X-ray shadow pictures, or light sensitive material for X-ray photography purposes may be employed. In either event, and particularly where visual examination is made with a fluoroscopic screen, the operator or examiner must necessarily stand alongside of the table in position to view the screen, or operate controls required in X-ray photography. When so standing alongside of the table, the operators mid section is likely to be disposed at the slot provided for the accommodation of the operating handles of the under top carriage, in position exposed to stray X-ray radiation through said slot from the source located beneath the table top panel.

fsince it is desirable to protect the operator, as much as possible, from exposure to X-rays, the present invention has for its important object the'provision of simple and inexpensive means for-screening the aforeaid slot against passage therethrough of X-rays whenever the over table carriage structure is in operation in conjunction with an X-ray source disposed beneath the table top.

Another important object is to arrange such s'lot screening means to automatically assume screening position when the over table carriage structure is in use, without requiring the operator to take any special steps to mount the screen in screening position, thereby eliminating the danger of failure vto provide the screening effect through the operators negligence.

vAnother important object is to provide screening means of the character mentioned, which will automatically be positioned in slot screening position as the result of moving the under panel cassette carriage to either end of the table in order` to allow the over panel carriage structure to be placed in operation.

' Another object is to provide screen means comprising a pair of folding, panel-like legs of material relatively impervious to X-rays, between the under panel carriage and each end of the table, so that one or other of said pairs of folding legs may be disposed in screening position across the slot in response to disposition of the under panel carriage in offset position at one end or the other of the table.

Another important object is to utilize one or both of 'said relatively foldable leg pairs for the purpose yof supporting electrical conductor means for energizing electrical apparatus carried on the under panel carriage, and for electrically controlling the operation of the same. The foregoing and numerous other important objects, advantages, and inherent functions of the invention will become apparent as the same is more fully understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment of the invention. Referring to the drawings: '-j'Fig. 1 is a perspective view of a structure comprising a support table embodying the present invention;

Fig-'2 is a sectional view taken substantially along the line 2-2' in Fig. 1; Fig. 3 is a perspective view of the structure as seen from the under side of the table;

Figs, 4, 5, and 6 are sectional views of somewhat diagrammatic character, taken substantially along the line 4-4 in Fig. l, to illustrate structure embodying the present invention in several relatively shifted positions;

Fig. 7 is an enlarged sectional view taken substantially along the line 'I-I in Fig. 5;

Fig. 8 is an enlarged sectional view taken substantially along the line 8-8 in Fig. 7;

Figs. 9 and 10 are enlarged sectional views taken substantially along the lines 9-9 and Ill-I0 in Fig. 8; and

Figs. 1l and 12 are enlarged views of portions of the structure shown in Fig. 7.

To illustrate the invention, the drawings show a compact apparatus adapted for fluoroscopic examination and radiographic purposes, the same comprising a table-like support structure I I, including a table frame I2 and a top panel I3, on which an object to be examined may be disposed. While the frame I2 may be of any preferred construction to provide adequate rigidity, it preferably consists of hollow, box-like members, including longitudinally extending side members and transverse members interconnecting the side members at the opposite ends of the frame. The transverse and side members are preferably formed of heavy gauge sheet metal, such as steel, which is relatively impervious to X-rays. If desired, the frame members may be lined with lead sheets for X-ray screening purposes. One of the side members of the frame also preferably carries a skirt I2 comprising a dependent plate, as of steel, which may be lined with lead for X-rayI screening purposes hereinafter more fully explained. The structure also includes associated facilities for radiographic purposes, that is to say, the making of X-ray photographs of an object thereon by means of a source of X-rays (not shown) disposed above the table, in conjunction with means for supporting X-ray sensitive material beneath the top panel of the table, such means comprising an under panel carriage I4.

The associated equipment may also include apparatus for the luoroscopic examination as well as X-ray photography, or radiography, of an object, supported on the table, by means of an X-ray source, S, disposed beneath the top panel in position to emit a beam of X-rays in a direction upwardly through the panel and an object thereon, such means including an over panel carriage structure I5 adapted to support, as at I6, an X-ray sensitive iluoroscopic screen above the table, in position for fluoroscopic examination of an object on the table. The over table carriage structure may also be formed to support X-ray sensitive material in position for radiographic purposes above the table.

While the illustrated apparatus has many convenient features, the present invention is not necessarily restricted to the particular form or arrangement of parts which are shown merely for the purpose of illustrating the operation of the present invention, which comprises protective screening means in conjunction with the table structure and associated equipment, as hereinafter more fully described. In this connection, it will be obvious that the X-ray source, used above the table, in conjunction with sensitive material in the under panel carriage I4, may, as shown in the previously mentioned Grobe Patent No. 2,315,786, be mounted on the over panel carriage structure I5. It will be obvious, also, that facilities may be provided for utilizing such X-ray source in position selectively above and below the panel I3, in the, manner taught in said-Grobe als-sacem patentA aforesaid. Such: X-ray source# obviously,

when'ipositionedabove thepanel, may cooperate with light sensitive-materiall carried in the'under.

panelcarr-iage I4ifor radiographic purposes; andwhen disposed beneath the panel, may be emscopicexamination or radiographic purposes;

The -apparatus herein illustrated.` contemplates the support ofthe X-ray source on. a supportV structure separate from the over panel' structureV I5. To this end, the X-raysourcerv may bes'ep--I ara'tely supported inl the'manner illustratedand described in a co pending application for U, S. Letters Patent onrX-Ray Apparatus, Serial No; 95,752, led May 27, 1949. An X-ray's'our'ce supported in such separate fashion may,fatf will, be adjusted in position above the-panel I3vr for emission of X-rays downwardly for radiographic pur-- poses on sensitive material supported on'the'un'- der panel carriage I4, and in position beneaththe panel to project X-rays upwardly therethrough upon av fluorescent screen or` light sensitive mafterial supported, as at I6, in the over panel carriage. v

The illustrated apparatus comprises a pedestal or base I'I, on which the table frame I2 may be tiltably mounted to support the object under examination' in either horizontal or in any relatively tilted position. As will be apparent, however, the present invention is not necessarily limited to a relatively tiltable table structure, but may be embodied to advantagev in a stationary table, if desired. Where a tilting table is employed, however', the lsame may, and preferably does, comprise astructure of the character illustrated in the co.. pending application for U. S. Letters Patent for X-Ray Apparatus, Serial No. 95,752, led May 2"?, 1949. In such structure the'frame I2 may be provided with tracks I8 along the opposite sides ofand beneath the top panel I3 for guiding and supporting the under panel carriage I4 for longitudinal movement immediately beneath the top panel, the carriage being preferably provided with suitable wheels or rollers having engagement-with the tracks; and the carriage may be provided with rollers I9 at the opposite ends of the carriage in position to bear upon the under side of the table top I3. If desired, the carriage d may be connected with counterbalancing means, through suitable cords operating on pulleys or sheaves on the table frame, to counterbalance the weight ofthe carriage and facilitate movementthereof. along the tracks, regardless of the tilted position ofr the table structure on its pedestal or base I1.

A handle 2i] may be provided on the carriage in position projecting throughv an elongated slot or opening 2I in thefra-me I4; immediately beneath a longitudinal side edge of the top panel I3, such handle beingprovided for shifting the under panel carriage longitudinally from end to end of the table structure.` Said handle, if desired, may be arranged for manual operation to clamp or lock the carriage I4 in any position of longitudinal adjustment on the table frame; or a separate clamping or locking handle may be provided in position extending through the slotv 2I.

The carriage I4 comprises frame means providing support for receiving a case orcassette containing a sheet or film of X-ray sensitive material. Such cassette may be loaded into or vmounted in the carriage I'll by insertion of the cassette edgewise through the slot 2I. Said car- 62 riage may, and preferably does, embody aBucky diaphragm structure, B, mounted therein in` poisition extending between the cassette supporti andthe table top. The carriage I 4 preferably also includes motive means, M1,A for shifting the.:

Bucky diaphragm, in the` manner taught, for example, in U. S. Letters` Patent-No. 2,062,562; issued December l, 1936, on thelinvention of'Roy` E'. Dent'. Such Bucky shifting mechanism mayy be adjusted, and the operation thereof corrtrolled, by suitable handle means 22' extending;

from the carriage Ill through the slot-like opening 2I. Power for the operation and controli of the Buck-yV shifting mechanism may be de livered through suitable conductors 23` The table frame I2 may also be' provided withA tracks 24, beneath the tracks I'8,-- -for mounting the over panel carriage structure I5 for movement longitudinally of the table frame. To this-r end, the structure I5 may comprise a carriage; frame 25, formed with rollers adapted-to. ride the.: tracks 24 between the opposite ends of the table;

frame I2. This carriage frame, if desiredfmay.l

be eounterbalanced,

desired position of adjustment. longitudinally of the table frame Supported on the' frame 25for.

sliding movement in a directiontransversely of'y the table, isa sub-frame 261havingzportions` ex.- tending' outwardly of and beneath the side of the table frame I2, preferablyv opposite.v from. the.`

slot 2 I, said sub-frame 26 -carrying theover panel' support structure I5 thereon. The. sub-frame 2li,y

frame, which in-turn, by'suitableroller means-,isv

carried slidably on the carriage:frameY 25. Manually operable means may be Aprovided. for secur ing the sub-frame 26Min any relatively adjusted' positionwith respectrto' the-carriage frame'25rin a direction'transversely of the tablestructure.

' A suitable structure-2l;` such as'the'mechanismi illustrated and described in an application for U. S. Letters Patent on the invention of lviueller.v

and Burgeson, shortly to be filed, maybe mount-- ed on the ove'r panelcarria'ge structure I 5.for`the. purpose of supporting a fluorescent screenabove the panel I3in position for uoroscopic exami,, nation of an object on the table, in conjunction with a light sourcedisposed beneath the panel I3, as on the sub-frame 26, such` structure 21 preferably embodying support means for posi,- tioning X-raysensitiveV material," in a suitable cassette, at will, in position, as at I6, for. radiographic purposes, such mechanismallowing an X-ray photograph to be made of an` object viewed fluoroscopically, substantially instantalneously, by appropriate-action of the observer.

The X-ray sourcein position- 'beneath' the table, for cooperation' with the mechanism 211, if desired may be permanently mounted on" the subframe 2'6 ata suitable source seat formed in said sub-frame. So mounted, the X'ray source will be permanently positioned in alinecl registration with th'eV fluorescent screen at I6 and with the position occupied by a film cassette when projected into position for X-ray photography purposes. Alternately, as heretofore suggested; the sub-frame 26 may be formed vWitlr source seating means adapted detachablyfto receive-a suitable X-ray source in operative position thereon, whereby such' sourcemay be selectively employed in position on thefsub-frame 2 be@ and manually operablef. means may be provided'for anchoring itinlany.'

neath the table top panel, and in position above the table top to cooperate with sensitive material in the under panel carriage I4.

When the structure 21 is in operation for fluoroscopic examination or radiography in conjunction with a light source mounted on the subframe 26, it will be apparent that the under panel carriage I4 will necessarily be disposed in position either at one end of the table, as shown in Fig. 4, or at the opposite end of the table, as shown in Fig. 6, thus leaving the remaining portions of the table unobstructed for iluoroscopy or radiography by means of the mechanism 21. It will be seen, also, that during iluoroscopy or radiography by means of the mechanism 21, the operator or observer must necessarily stand alongside of the table opposite the viewing screen location at I6. In such position, the observers mid-section will necessarily be disposed opposite the lslot 2I in substantial registration with the operating X-ray source on the sub-frame 25, thus being in danger of exposing the operator's midsection to undesirable X-ray radiation as the result of penetration of stray X-rays from the source through the unguarded opening 2l.

The frame I2 and its skirt I2. as heretofore pointed out, tend to screen the operator against undue X-ray exposure. The edge of the top panel I3 may also be enclosed in a metal binding having some X-ray screening effect. The opening 2I, however, is necessarily of substantial width, of the order of 3-4 inches, and is necessarily unobstructed to allow adjustment of the carriage I4 freely to any position between the opposite ends of the table frame, and to permit a cassette loaded with sensitive material to be mounted in the carriage I4 in any adjusted position thereof lengthwise of the table structure.

It is an important object of the present invention to provide automatic means for screening the opening 2I against such penetration of X- rays therethrough when the over panel apparatus 21 is in operation. To this end, automatically operating screen means 28 is provided, which not only disposes an adequate screen across the slot 2l whenever the over panel apparatus 21 is in operation, but also allows free and unobstructed movement of the under panel carriage I4 longitudinally of the table at all times. The screen means 28, also, is of exceedingly simple and inexpensive character and may be provided without materially increasing the cost of the apparatus.

The protection screen mechanism 28 comprises a set or pair of relatively foldable leg panels 29 and 30l at each end of the under panel carriage I4,'each leg pair 29 and 30 being pivotally connected together, as at 3I, at the meeting ends of the legs. The end of the leg 30, remote from the medial pivot 3I, is pivoted, as at 32, on the carriage I4, at a corner thereof adjacent the slot 2l. The other leg 29, at the end thereof remote from the medial pivot 3I, is pivoted, as at 33, on the main table frame I2 opposite an endlof the slot 2|.I A folding screen, comprising a leg 29 and a leg 30, is thus connected between each end of the carriage I4 and the corresponding end of the frame I2, the folding screens being sized and mounted so that, when the carriage I4 is in position at either end of the table, one of the screens will be in snugly folded position between the carriage I4 and said end of the frame i2, while the other of them will be straightened out in position occupying a flat plane and covering the slot 2| between the carriage I4 and the opposite end of the frame I2.

The two folding screens may comprise leg parts of identical configuration, said parts preferably comprising metal stampings, as of steel, carrying, if desired, sheets of lead for additional X-ray protection. As shown, the screen legs 29 and 3i] comprise sheet metal channel members 34 and 35, having upper and lower marginal flanges 35 on the members 29 and 31 on the members 30, such angesbeing formed for intertting or nested relationship at the meeting ends of thelegs, whereby the pivots 3l may comprise simple stems 38 extending through perforations in the flanges 36 and 31 to relatively hinge the legs 29 and 30, suitable nuts 39, fastened on the opposite ends of the pivot pins 38, being provided to secure the legs on the pivot pins. The legs 29 may be pivotally secured on the frame I2 by means of pivot pins 40, mounted on the frame I2 as by means of nuts 4I threaded onrthe pins 40, said pins 49 extending through suitable openings formed in the flanges 36 and secured in place, as by means of nuts 42. The pivot remote ends of the leg members 39 may be pivotally secured to the carriage I4 by means of sheet metal panel members forming brackets 43 on the carriage, and pivot pins 44 pivotally interconnecting the ends of the anges 31 with the flanges of the brackets 43.

f desired, one or other or both of the legs 29 and 3i] of each folding screen may be provided with resilient buffer members 45, as of rubberlike material, mounted to minimize noise of engagement of the leg members when relatively folded together. The legs 29 and 30 forming one or both of the screens may be provided at intervals with conductor clips 46 for the purpose of securing the conductors 23 to the legs, said conductors being preferably looped opposite the pivots 3l. The conductors 23, which connect with electrical mechanism in the carriage Iii and with electrical equipment on or outwardly of the table frame I2, may thus be supported in neat, orderly fashion and prevented from hanging loosely and from becoming entangled with the several relatively movable elements of the structure. To facilitate electrical connections, the conductors 23 may be connected at their opposite ends on connection terminal panels 41 and '48, respectively mounted on the frame I2, near the pivoted end of a screen member 29, and on the carriage I4, near the pivoted end of a screen member 38, in position for electrical connection with the Bucky operating aparatus, M.

It is thought that the invention and its numerous attendant advantages will be fully understood from the foregoing description, and it is obvious that numerous changes may be made in the form, construction and arrangement of the several parts without departing from the spirit or scope of the invention, or sacrificing any of its attendant advantages, the form herein disclosed being a preferred embodiment for the purpose of illustrating the invention.

The invention is hereby claimed as follows:

l. In an X-ray apparatus comprising a support table structure including a frame and a panel forming a top on which to support an object for X-ray exposure, an under panel carriage for X-ray sensitive material movable on said frame, longitudinally of and beneath said panel, between the opposite ends of said table structure, in position to cooperate with an X-ray source supported above the panel, and means for supporting X-ray sensitive material in position, above the panel. to cooperate with an X-ray afsefnaee source disposed? beneath the:V panel; vwherein the tablestructure is formed with-an elongated opening, beneath the panel affordingV access to'said under p anel carriage, inanyv longitudinally adjusted position thereof in the table structure, the.,` combination, with said frame` andr carriage, orX-ray opaque screen means vcomprisingjrelatively hinged plates at least one of which-ispivotally connected with the carriage and another of which is supported by the frame, said plates being movable, in response to movement of said carriage toward one end of said frame, into position to screen the said opening, between said carriage and the opposite end of the frame.

2. In an X-ray apparatus comprising a support table structure including a frame and a panel forming a top on which to support an object for X-ray exposure, an under panel carriage for X-ray sensitive material movable on said frame, longitudinally of and beneath said panel, between the opposite ends of said table structure, in position to cooperate with an X-ray source supported above the panel, and means for supporting X-ray sensitive material in position, above the panel, to cooperate with an X-ray source disposed beneath the panel, wherein the table structure is formed with an elongated opening beneath the panel affording access to said under panel carriage, in any longitudinally adjusted position thereof in the table structure, the combination with said frame and carriage, of X-ray opaque screen means for said opening, comprising a pair of plates of X-ray opaque material relatively pivoted at their adjacent ends and having remote ends respectively pivoted on said carriage and on said frame, adjacent an end thereof.

3. In an X-ray apparatus comprising a support table structure including a frame and a panel forming a top on which to support an object for X-ray exposure, an under panel carriage for X-ray sensitive material movable on said frame, longitudinally of and beneath said panel, between the opposite ends of said table structure, in position to cooperate with an X-ray source supported above the panel, and means for supporting X-ray sensitive material in position, above the panel, to cooperate with an X-ray source disposed beneath the panel, wherein the table structure is formed with an elongated opening vbeneath the panel affording access to said under panel carriage, in anyk longitudinally adjusted position thereof in the table structure, the combination, with said frame and carriage, of X-ray opaque screen means for said opening, comprising a pair of elongated plates or material relatively impervious to X-rays, having pivotally interconnected ends and remote ends respectively pivoted on said carriage, adjacent said opening, and on said frame, adjacent an end thereof and inwardly of said opening, in position to extend in substantially co-planar relation in said opening when said carriage is moved toward one end of said frame, and to fold one plate against the other when said carriage is moved toward the opposite end of said frame.

4. In an X-ray apparatus comprising a support table structure including a frame and a panel forming a top on which to support an object for X-ray exposure, an under panel carriage for X-ray sensitive material movable on said frame, longitudinally of and beneath said panel, between the opposite ends of said table structure, in position to cooperate with an X-ray source supported above:` the panel, and means. for supporting-X-ray sensitive material in position, above the-panel', to cooperate;withy anfX-ray source disposed' beneathf the panel, wherein '.the .table structure is formed with an elongated opening beneath the panell.afi`ording access-to said under panel carriage,E in anyA longitudinally .adjusted position thereof in the table structureincluding electrically operable equipment supported on said carriage, the combination, with said frame and carriage, of X-ray opaque screen means for said opening, comprising a pair of plates relatively pivoted at their adjacent ends and having remote ends respectively pivoted on said carriage and on said frame adjacent an end thereof, and conductors electrically connected with said operable equipment and extending thence from the carriage to said frame in position successively supported on said relatively pivoted plates.

5. In an X-ray apparatus comprising a support table structure including a frame and a panel forming a top on which to support an object for X-ray exposure, an under panel carriage for X-ray sensitive material movable on said frame, longitudinally of and beneath said panel, between the opposite vends of said table structure, in position to cooperatewith an X-ray source supported above the panel, and means for supporting X-ray sensitive material in position. above the panel, to cooperate with an X-ray source disposed beneath the panel, wherein the table structure is formed with an elongated opening beneath the panel affording access to said under panel carriage, in any longitudinally adjusted position thereof in the table structure, the combination, with said frame and carriage, of X- ray opaque protective screen means comprising a folding screen connected on and between each of the opposite ends of said carriage and the corresponding ends of the frame, each of said folding screens embodying a pair of plates relatively pivoted at their adjacent ends and having remote ends respectively pivoted on said carriage and on said frame, adjacent an end thereof, in position to fold together between the carriage and the end of the frame when the carriage is moved on the frame toward said end.

6. In an X-ray apparatus comprising a support table structure including a frame and a panel forming a top on which to support an object for X-ray exposure, an under panel carriage for X-ray sensitive material movable on said frame, longitudinally of and beneath said panel, between the opposite ends of said table structure, in position to cooperate with an X-ray source supported above the panel, and means for supporting X-ray sensitive material in position,

kabove the panel, to cooperate with an X-ray source disposed beneath the panel, wherein the table structure is formed with an elongated opening beneath the panel affording access to said under panel carriage, in any longitudinally adjusted position thereof in the table structure, the combination, with said frame and carriage, of X-ray opaque screen means for said opening, comprising a pair of elongated plates of material relatively impervious to X-rays having pivotally interconnected ends and remote ends respectively pivoted on said carriage, adjacent said opening, and on said frame, adjacent an end thereof and inwardly of said opening, in position to extend in substantially co-planar relation in said opening when said carriage is moved toward one end of said frame, and to fold one plate against 11 the other and between the carriage and the opposite end of the frame When said carriage is moved toward the said opposite end of the frame.

ARTHUR J. KIZAUR.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date Clark Mar. 4, 1890 Egress et a1. May 9, 1933 Page Nov. 14, 1939 Grobe Apr. 6, 1943 Boyd July 8, 1947 Haupt Aug. 26, 1947 

